Mitral regurgitation characteristically presents with which murmur?

• A. Decrescendo diastolic murmur at the left sternal border
• B. Continuous murmur radiating to the back
• C. Systolic murmur at the left upper sternal border
• D. High-pitched, blowing holosystolic murmur heard at the apex

Answer: (D)

Mitral regurgitation causes blood to leak backward from the left ventricle into the left atrium during systole, producing a holosystolic murmur that starts with S1 and continues through S2. It is typically high-pitched and blowing in quality and is best heard at the cardiac apex (left 5th intercostal space, midclavicular line) with radiation toward the axilla. This combination—holosystolic timing, blowing quality, and apex location with axillary radiation—is the hallmark of mitral regurgitation, making it the best match for this presentation.

The other patterns don’t fit MR: a diastolic decrescendo murmur at the left sternal border points to aortic regurgitation, which occurs in diastole; a continuous murmur radiating to the back suggests patent ductus arteriosus; a systolic murmur at the left upper sternal border is more typical of conditions like pulmonic stenosis or flow murmurs, not MR.